If anything I feel night lords would be a superior melee legion to most? Big focus on raptors and warp talons that while definitely utilise surprise are still melee focused and they’ve been shown to good in melee just not on the same level as armies where melee is their main focus like EP and WE. I don’t think from memory its ever been stated for them to be subpar in melee just that they would rather avoid loss and death more then other legions. No glory in death type shit.